Minutes before the Love Letters tour begins, patrons line the bathroom sink at the Rosenbach Museum like doctors preparing surgery. Everyone must wash up before handling John Keats’ early 19th-century letter to Fanny Brawne, among other priceless documents.

“When we say ‘hands on,’ we mean it literally. People get to hold and get intimate with the documents,” says curator Farrar Fitzgerald.

“I guess ‘intimate’ is sort of an apt word to use when we’re talking about the Love Letters tour,” she adds with a laugh.

Fitzgerald assembled the tour in 2009, as interest in Keats peaked with the film “Bright Star,” and it has continued to be one of the most popular attractions on the Rosenbach roster.

Of course, A.S.W. Rosenbach mainly collected books and manuscripts — his collection remains one of the most revered in the world. But that didn’t stop him from nabbing a few valuable – and quite personal – love letters along the way. Among the authors of these unusual documents are Keats, Benjamin Rush, Marlene Dietrich and James Joyce.

With each tour group capped at 10, guests have a chance to ask as many questions as they please.

“Often visitors notice the way an author’s handwriting changes when they are becoming more passionate about what they’re writing,” says Fitzgerald. “There’s so much to discover just in looking at how the letter was formatted — how it was folded, the way the address was written, the formality of the language. All of this reflects the author and the time in which they lived.”